The present invention relates generally to timepieces, such as wristwatches, and in particular, to improved constructions and methodologies for maintaining accurate date information in such timepieces that comprise date rings. Typically timepieces referred to as “analog” or “quartz-analog” watches having hands for displaying time, and which drive the date rings as a function of the rotation of one or more gears, are applicable to this invention. In particular, the present invention provides an improved construction and methodology for maintaining an accurate date display using one date wheel to display the “ones” portion of the date reading and another date wheel to display the “tens” portion of the date reading. A two wheeled date display in this regard allows for the use of larger numbers and easier reading.
U.S. Patent Application Publication No. U.S. 2003/0193840 describes such a two-ringed date display system, wherein a motor and gearing system turn both the “ones” disc and the “tens” disc. In such an embodiment, the tens ring rotates 360° with each date increment of the ones ring, and the tens disc rotates 450° with each increment of the ones ring going from “9” to “0.” It is believed that this arrangement requires an unnecessarily amount of rotation of the tens disc.
The present invention is therefore preferably directed to a date display for an electromechanical timepiece which will be simple, requiring few pieces which are easily machined and whose reading will be easily seen because of the relatively large size of the numbers used. In addition, necessary motion of the mechanism is minimized thereby conserving energy. These and other objects of this invention will be revealed in the construction disclosed herein.